Tile-based user interface for Standard Edition. I like it a lot. It makes Windows Mobile much more easy to use but it also makes the homescreen more useful: as an example, you can look at your appointments for the day without leaving the home screen.

Bandwidth optimizations that result in a significant reduction in data usage. There could be as much as a 40% improvement for most users.

Enhanced S/MIME support – support for encrypted email and additional policies to enforce and manage S/MIME use are now included.

On-Device Encryption – a few customers have required full encryption of all email, calendars and tasks on the device. Previous versions support encryption of the storage card, email encryption and encryption of data stored in SQL Server CE.

Control of device features. This includes enabling/disabling the camera, browser, WiFi, text messaging, bluetooth, etc.

White List or Black List applications, as well as a policy to allow unsigned applications.